I found the answer to my question with a Google search that took me to an eHow file on how to get started with surveyor.
The solution (for anyone else that wants to play with the trains in the Toronto Railands Grand Tour in TR2006 in cab mode) is:
1. From the main menu choose "Surveyor" mode to make your own driving session.
2. Click any of the installed routes now appearing on the screen. Create a new session by clicking on the desired name within the installed routes and clicking "Load", and edit a session by clicking it within the routes and changing the trains, route and so forth.
2. Take advantage of the "Rules" the trains must follow during sessions by clicking "Edit Session Rules", clicking "Start-up Options" and finally selecting "Edit".
3. Change from "DCC Mode" to "Cab Mode".
4. From the Surveyor Menu "Save As" and modify the file name (so you won't override the original).
Your modified session should work the same as the original, except when you take control of a train by choosing "Abandon Schedule" for your driver, you will have full control of your throttle, brake, and all the other stuff in your cab.
(FWIW - this was my first hands-on experience with Surveyer!

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